The present invention relates to non-semiconductor microminiature electronic elements, and pertains particularly to an improved package and method of surface mounting of multi-section bobbins.
For many years, electronic circuit boards have been fabricated by interconnecting a plurality of electronic components, both active and passive, on a planar printed circuit board. Typically, this printed circuit board has comprised an Epoxy/fiberglass laminate substrate clad with a sheet of copper, which has been etched to delineate the conductive paths. Holes were drilled through terminal portions of the conductive paths for receiving electronic component leads, which were subsequently soldered thereto.
More recently, so-called surface mount technology has evolved to permit more efficient automatic mass production of circuit boards with higher component densities. With this approach, certain packaged components are automatically placed at preselected locations on top of a printed circuit board, so that their leads are registered with and lie on top of corresponding solder paths or pads. The printed circuit board is then processed by exposure to infrared or vapor phase soldering techniques to re-flow the solder, and thereby establish a permanent electrical connection between the leads and their corresponding conductive paths on the printed circuit board.
Among the electrical and electronic elements that must be surface mounted on PC boards are multi-section bobbins. A bobbin is a small insulated spool, which serves as a support for a coil or wire wound resistor. The current technique of surface mounting of a multi-section bobbin is by the surface mounting of flying leads, as illustrated in FIG. 1 of the drawings. The current technique of mounting is time consuming, difficult to machine wind and tap, and frequently results in reliability problems.
The increasing miniaturization of electrical and electronic elements and high density mounting thereof has created increasing problems with electrical isolation and mechanical interconnection. In particular, it creates more difficulty establishing reliable and efficient connection between fine gauge (AWG 24 to AWG 50) copper wires and terminals. Presently known interconnect methods severely limit the ability to provide density and reliable electrical and mechanical isolation between distinct egress or terminal points due to space limitations.
The prior art approach, as illustrated in FIG. 1, is to select an insulated bobbin 10 of suitable length, and wind a wire 11 forming a first coil 12 with a lead or terminal 13 at one end and a lead 14 at the other end. The wire is wound to form additional coils 15, 16 and 17, with leads 18, 19, and 20 for mounting and connection to a PC board. These leads are commonly called flying leads and are solder connected to a PC board. In addition, the lead is also frequently broken as the result of thermal expansion and contraction of the leads and/or terminals.
It is, therefore, desirable that an improved package and method of mounting of multi-section bobbins be available.